Prison Justice! Jailhouse Insiders Say 'Grim Sleeper' Faces Inmate Attack

Twisted trash collector Lonnie Franklin Jr., the sadistic serial killer known as "The Grim Sleeper," has been sentenced to death — but insiders say the psychopath will die from jailhouse justice before a formal execution!

"He will be forever in fear, looking over his shoulder," says a source, after a judge sentenced the creep, 63, to death on Aug. 10.

But the dirt-bag killer is unlikely to ever be put to death because of endless legal challenges over the state's lethal injection procedure.

So Franklin, who got his nickname because of the lengthy gap in his slayings — seven were killed between 1985 and 1988, and three more between 2002 and 2007 — will sweat out his days in California's San Quentin prison.

Labeled by prosecutors as "a psychopath who takes joy in inflicting pain on women and killing them," Franklin will likely be taken out by an inmate disgusted by his sickening crimes, instead, sources told Radar.